I felt like her tweet was unnecessary. The internet/twitter really wasn't talking about her until she made that tweet. Afterwards, I saw tweets directed to her said "I hope he leaves you," and "bitch bye, I'm a better wife to JT than you!"
I do think it's kinda weird she doesn't show up. Maybe she didn't feel like getting dolled up & just wanted to chill. I do feel like there are many females in this world that would happily marry Justin's sexy ass and physically support him at every award show